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/*++
/* NAME
/* xsasl_cyrus_server 3
/* SUMMARY
/* Cyrus SASL server-side plug-in
/* SYNOPSIS
/* #include <xsasl_cyrus_server.h>
/*
/* XSASL_SERVER_IMPL *xsasl_cyrus_server_init(server_type, path_info)
/* const char *server_type;
/* const char *path_info;
/* DESCRIPTION
/* This module implements the Cyrus SASL server-side authentication
/* plug-in.
/*
/* xsasl_cyrus_server_init() initializes the Cyrus SASL library and
/* returns an implementation handle that can be used to generate
/* SASL server instances.
/*
/* Arguments:
/* .IP server_type
/* The server type (cyrus). This argument is ignored, but it
/* could be used when one implementation provides multiple
/* variants.
/* .IP path_info
/* The base name of the SASL server configuration file (example:
/* smtpd becomes /usr/lib/sasl2/smtpd.conf).
/* DIAGNOSTICS
/* Fatal: out of memory.
/*
/* Panic: interface violation.
/*
/* Other: the routines log a warning and return an error result
/* as specified in xsasl_server(3).
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Initial implementation by:
/* Till Franke
/* SuSE Rhein/Main AG
/* 65760 Eschborn, Germany
/*
/* Adopted by:
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*
/* Wietse Venema
/* Google, Inc.
/* 111 8th Avenue
/* New York, NY 10011, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <sys/socket.h>
#include <stdlib.h>
#include <string.h>
/* Utility library. */
#include <msg.h>
#include <mymalloc.h>
#include <name_mask.h>
#include <stringops.h>
/* Global library. */
#include <mail_params.h>
/* Application-specific. */
#include <xsasl.h>
#include <xsasl_cyrus.h>
#include <xsasl_cyrus_common.h>
#if defined(USE_SASL_AUTH) && defined(USE_CYRUS_SASL)
#include <sasl.h>
#include <saslutil.h>
/*
* Silly little macros.
*/
#define STR(s) vstring_str(s)
/*
* Macros to handle API differences between SASLv1 and SASLv2. Specifics:
*
* The SASL_LOG_* constants were renamed in SASLv2.
*
* SASLv2's sasl_server_new takes two new parameters to specify local and
* remote IP addresses for auth mechs that use them.
*
* SASLv2's sasl_server_start and sasl_server_step no longer have the errstr
* parameter.
*
* SASLv2's sasl_decode64 function takes an extra parameter for the length of
* the output buffer.
*
* The other major change is that SASLv2 now takes more responsibility for
* deallocating memory that it allocates internally. Thus, some of the
* function parameters are now 'const', to make sure we don't try to free
* them too. This is dealt with in the code later on.
*/
#if SASL_VERSION_MAJOR < 2
/* SASL version 1.x */
#define SASL_SERVER_NEW(srv, fqdn, rlm, lport, rport, cb, secflags, pconn) \
sasl_server_new(srv, fqdn, rlm, cb, secflags, pconn)
#define SASL_SERVER_START(conn, mech, clin, clinlen, srvout, srvoutlen, err) \
sasl_server_start(conn, mech, clin, clinlen, srvout, srvoutlen, err)
#define SASL_SERVER_STEP(conn, clin, clinlen, srvout, srvoutlen, err) \
sasl_server_step(conn, clin, clinlen, srvout, srvoutlen, err)
#define SASL_DECODE64(in, inlen, out, outmaxlen, outlen) \
sasl_decode64(in, inlen, out, outlen)
typedef char *MECHANISM_TYPE;
typedef unsigned MECHANISM_COUNT_TYPE;
typedef char *SERVEROUT_TYPE;
typedef void *VOID_SERVEROUT_TYPE;
#endif
#if SASL_VERSION_MAJOR >= 2
/* SASL version > 2.x */
#define SASL_SERVER_NEW(srv, fqdn, rlm, lport, rport, cb, secflags, pconn) \
sasl_server_new(srv, fqdn, rlm, lport, rport, cb, secflags, pconn)
#define SASL_SERVER_START(conn, mech, clin, clinlen, srvout, srvoutlen, err) \
sasl_server_start(conn, mech, clin, clinlen, srvout, srvoutlen)
#define SASL_SERVER_STEP(conn, clin, clinlen, srvout, srvoutlen, err) \
sasl_server_step(conn, clin, clinlen, srvout, srvoutlen)
#define SASL_DECODE64(in, inlen, out, outmaxlen, outlen) \
sasl_decode64(in, inlen, out, outmaxlen, outlen)
typedef const char *MECHANISM_TYPE;
typedef int MECHANISM_COUNT_TYPE;
typedef const char *SERVEROUT_TYPE;
typedef const void *VOID_SERVEROUT_TYPE;
#endif
#ifndef NO_IP_CYRUS_SASL_AUTH
#define USE_IP_CYRUS_SASL_AUTH
#endif
/*
* The XSASL_CYRUS_SERVER object is derived from the generic XSASL_SERVER
* object.
*/
typedef struct {
XSASL_SERVER xsasl; /* generic members, must be first */
VSTREAM *stream; /* client-server connection */
sasl_conn_t *sasl_conn; /* SASL context */
VSTRING *decoded; /* decoded challenge or response */
char *username; /* authenticated user */
char *mechanism_list; /* applicable mechanisms */
} XSASL_CYRUS_SERVER;
/*
* Forward declarations.
*/
static void xsasl_cyrus_server_done(XSASL_SERVER_IMPL *);
static XSASL_SERVER *xsasl_cyrus_server_create(XSASL_SERVER_IMPL *,
XSASL_SERVER_CREATE_ARGS *);
static void xsasl_cyrus_server_free(XSASL_SERVER *);
static int xsasl_cyrus_server_first(XSASL_SERVER *, const char *,
const char *, VSTRING *);
static int xsasl_cyrus_server_next(XSASL_SERVER *, const char *, VSTRING *);
static int xsasl_cyrus_server_set_security(XSASL_SERVER *, const char *);
static const char *xsasl_cyrus_server_get_mechanism_list(XSASL_SERVER *);
static const char *xsasl_cyrus_server_get_username(XSASL_SERVER *);
/*
* SASL callback interface structure. These call-backs have no per-session
* context.
*/
#define NO_CALLBACK_CONTEXT 0
static sasl_callback_t callbacks[] = {
{SASL_CB_LOG, (XSASL_CYRUS_CB) &xsasl_cyrus_log, NO_CALLBACK_CONTEXT},
{SASL_CB_LIST_END, 0, 0}
};
/* xsasl_cyrus_server_init - create implementation handle */
XSASL_SERVER_IMPL *xsasl_cyrus_server_init(const char *unused_server_type,
const char *path_info)
{
const char *myname = "xsasl_cyrus_server_init";
XSASL_SERVER_IMPL *xp;
int sasl_status;
#if SASL_VERSION_MAJOR >= 2 && (SASL_VERSION_MINOR >= 2 \
|| (SASL_VERSION_MINOR == 1 && SASL_VERSION_STEP >= 19))
int sasl_major;
int sasl_minor;
int sasl_step;
/*
* DLL hell guard.
*/
sasl_version_info((const char **) 0, (const char **) 0,
&sasl_major, &sasl_minor,
&sasl_step, (int *) 0);
if (sasl_major != SASL_VERSION_MAJOR
#if 0
|| sasl_minor != SASL_VERSION_MINOR
|| sasl_step != SASL_VERSION_STEP
#endif
) {
msg_warn("incorrect SASL library version. "
"Postfix was built with include files from version %d.%d.%d, "
"but the run-time library version is %d.%d.%d",
SASL_VERSION_MAJOR, SASL_VERSION_MINOR, SASL_VERSION_STEP,
sasl_major, sasl_minor, sasl_step);
return (0);
}
#endif
if (*var_cyrus_conf_path) {
#ifdef SASL_PATH_TYPE_CONFIG /* Cyrus SASL 2.1.22 */
if (sasl_set_path(SASL_PATH_TYPE_CONFIG,
var_cyrus_conf_path) != SASL_OK)
msg_warn("failed to set Cyrus SASL configuration path: \"%s\"",
var_cyrus_conf_path);
#else
msg_warn("%s is not empty, but setting the Cyrus SASL configuration "
"path is not supported with SASL library version %d.%d.%d",
VAR_CYRUS_CONF_PATH, SASL_VERSION_MAJOR,
SASL_VERSION_MINOR, SASL_VERSION_STEP);
#endif
}
/*
* Initialize the library: load SASL plug-in routines, etc.
*/
if (msg_verbose)
msg_info("%s: SASL config file is %s.conf", myname, path_info);
if ((sasl_status = sasl_server_init(callbacks, path_info)) != SASL_OK) {
msg_warn("SASL per-process initialization failed: %s",
xsasl_cyrus_strerror(sasl_status));
return (0);
}
/*
* Return a generic XSASL_SERVER_IMPL object. We don't need to extend it
* with our own methods or data.
*/
xp = (XSASL_SERVER_IMPL *) mymalloc(sizeof(*xp));
xp->create = xsasl_cyrus_server_create;
xp->done = xsasl_cyrus_server_done;
return (xp);
}
/* xsasl_cyrus_server_done - dispose of implementation */
static void xsasl_cyrus_server_done(XSASL_SERVER_IMPL *impl)
{
myfree((void *) impl);
sasl_done();
}
/* xsasl_cyrus_server_create - create server instance */
static XSASL_SERVER *xsasl_cyrus_server_create(XSASL_SERVER_IMPL *unused_impl,
XSASL_SERVER_CREATE_ARGS *args)
{
const char *myname = "xsasl_cyrus_server_create";
char *server_addr_port = 0;
char *client_addr_port = 0;
sasl_conn_t *sasl_conn = 0;
XSASL_CYRUS_SERVER *server = 0;
int sasl_status;
if (msg_verbose)
msg_info("%s: SASL service=%s, realm=%s",
myname, args->service, args->user_realm ?
args->user_realm : "(null)");
/*
* The optimizer will eliminate code duplication and/or dead code.
*/
#define XSASL_CYRUS_SERVER_CREATE_ERROR_RETURN(x) \
do { \
if (server) { \
xsasl_cyrus_server_free(&server->xsasl); \
} else { \
if (sasl_conn) \
sasl_dispose(&sasl_conn); \
} \
XSASL_CYRUS_SERVER_CREATE_RETURN(x); \
} while (0)
#define XSASL_CYRUS_SERVER_CREATE_RETURN(x) \
do { \
if (server_addr_port) \
myfree(server_addr_port); \
if (client_addr_port) \
myfree(client_addr_port); \
return (x); \
} while (0)
/*
* Set up a new server context.
*/
#define NO_SECURITY_LAYERS (0)
#define NO_SESSION_CALLBACKS ((sasl_callback_t *) 0)
#define NO_AUTH_REALM ((char *) 0)
#if SASL_VERSION_MAJOR >= 2 && defined(USE_IP_CYRUS_SASL_AUTH)
/*
* Get IP address and port of local and remote endpoints for SASL. Some
* implementation supports "[ipv6addr]:port" and "ipv4addr:port" (e.g.,
* https://illumos.org/man/3sasl/sasl_server_new), They still support the
* historical "address;port" syntax, so we stick with that for now.
*/
server_addr_port = (*args->server_addr && *args->server_port ?
concatenate(args->server_addr, ";",
args->server_port, (char *) 0) : 0);
client_addr_port = (*args->client_addr && *args->client_port ?
concatenate(args->client_addr, ";",
args->client_port, (char *) 0) : 0);
#else
/*
* Don't give any IP address information to SASL.
*/
#endif
if ((sasl_status =
SASL_SERVER_NEW(args->service, var_myhostname,
args->user_realm ? args->user_realm : NO_AUTH_REALM,
server_addr_port, client_addr_port,
NO_SESSION_CALLBACKS, NO_SECURITY_LAYERS,
&sasl_conn)) != SASL_OK) {
msg_warn("SASL per-connection server initialization: %s",
xsasl_cyrus_strerror(sasl_status));
XSASL_CYRUS_SERVER_CREATE_ERROR_RETURN(0);
}
/*
* Extend the XSASL_SERVER object with our own data. We use long-lived
* conversion buffers rather than local variables to avoid memory leaks
* in case of read/write timeout or I/O error.
*/
server = (XSASL_CYRUS_SERVER *) mymalloc(sizeof(*server));
server->xsasl.free = xsasl_cyrus_server_free;
server->xsasl.first = xsasl_cyrus_server_first;
server->xsasl.next = xsasl_cyrus_server_next;
server->xsasl.get_mechanism_list = xsasl_cyrus_server_get_mechanism_list;
server->xsasl.get_username = xsasl_cyrus_server_get_username;
server->stream = args->stream;
server->sasl_conn = sasl_conn;
server->decoded = vstring_alloc(20);
server->username = 0;
server->mechanism_list = 0;
if (xsasl_cyrus_server_set_security(&server->xsasl, args->security_options)
!= XSASL_AUTH_OK)
XSASL_CYRUS_SERVER_CREATE_ERROR_RETURN(0);
XSASL_CYRUS_SERVER_CREATE_RETURN(&server->xsasl);
}
/* xsasl_cyrus_server_set_security - set security properties */
static int xsasl_cyrus_server_set_security(XSASL_SERVER *xp,
const char *sasl_opts_val)
{
XSASL_CYRUS_SERVER *server = (XSASL_CYRUS_SERVER *) xp;
sasl_security_properties_t sec_props;
int sasl_status;
/*
* Security options. Some information can be found in the sasl.h include
* file.
*/
memset(&sec_props, 0, sizeof(sec_props));
sec_props.min_ssf = 0;
sec_props.max_ssf = 0; /* don't allow real SASL
* security layer */
if (*sasl_opts_val == 0) {
sec_props.security_flags = 0;
} else {
sec_props.security_flags =
xsasl_cyrus_security_parse_opts(sasl_opts_val);
if (sec_props.security_flags == 0) {
msg_warn("bad per-session SASL security properties");
return (XSASL_AUTH_FAIL);
}
}
sec_props.maxbufsize = 0;
sec_props.property_names = 0;
sec_props.property_values = 0;
if ((sasl_status = sasl_setprop(server->sasl_conn, SASL_SEC_PROPS,
&sec_props)) != SASL_OK) {
msg_warn("SASL per-connection security setup; %s",
xsasl_cyrus_strerror(sasl_status));
return (XSASL_AUTH_FAIL);
}
return (XSASL_AUTH_OK);
}
/* xsasl_cyrus_server_get_mechanism_list - get available mechanisms */
static const char *xsasl_cyrus_server_get_mechanism_list(XSASL_SERVER *xp)
{
const char *myname = "xsasl_cyrus_server_get_mechanism_list";
XSASL_CYRUS_SERVER *server = (XSASL_CYRUS_SERVER *) xp;
MECHANISM_TYPE mechanism_list;
MECHANISM_COUNT_TYPE mechanism_count;
int sasl_status;
/*
* Get the list of authentication mechanisms.
*/
#define UNSUPPORTED_USER ((char *) 0)
#define IGNORE_MECHANISM_LEN ((unsigned *) 0)
if ((sasl_status = sasl_listmech(server->sasl_conn, UNSUPPORTED_USER,
"", " ", "",
&mechanism_list,
IGNORE_MECHANISM_LEN,
&mechanism_count)) != SASL_OK) {
msg_warn("%s: %s", myname, xsasl_cyrus_strerror(sasl_status));
return (0);
}
if (mechanism_count <= 0) {
msg_warn("%s: no applicable SASL mechanisms", myname);
return (0);
}
server->mechanism_list = mystrdup(mechanism_list);
#if SASL_VERSION_MAJOR < 2
/* SASL version 1 doesn't free memory that it allocates. */
free(mechanism_list);
#endif
return (server->mechanism_list);
}
/* xsasl_cyrus_server_free - destroy server instance */
static void xsasl_cyrus_server_free(XSASL_SERVER *xp)
{
XSASL_CYRUS_SERVER *server = (XSASL_CYRUS_SERVER *) xp;
sasl_dispose(&server->sasl_conn);
vstring_free(server->decoded);
if (server->username)
myfree(server->username);
if (server->mechanism_list)
myfree(server->mechanism_list);
myfree((void *) server);
}
/* xsasl_cyrus_server_auth_response - encode server first/next response */
static int xsasl_cyrus_server_auth_response(int sasl_status,
SERVEROUT_TYPE serverout,
unsigned serveroutlen,
VSTRING *reply)
{
const char *myname = "xsasl_cyrus_server_auth_response";
unsigned enc_length;
unsigned enc_length_out;
/*
* Encode the server first/next non-error response; otherwise return the
* unencoded error text that corresponds to the SASL error status.
*
* Regarding the hairy expression below: output from sasl_encode64() comes
* in multiples of four bytes for each triple of input bytes, plus four
* bytes for any incomplete last triple, plus one byte for the null
* terminator.
*/
if (sasl_status == SASL_OK) {
vstring_strcpy(reply, "");
return (XSASL_AUTH_DONE);
} else if (sasl_status == SASL_CONTINUE) {
if (msg_verbose)
msg_info("%s: uncoded server challenge: %.*s",
myname, (int) serveroutlen, serverout);
enc_length = ((serveroutlen + 2) / 3) * 4 + 1;
VSTRING_RESET(reply); /* Fix 200512 */
VSTRING_SPACE(reply, enc_length);
if ((sasl_status = sasl_encode64(serverout, serveroutlen,
STR(reply), vstring_avail(reply),
&enc_length_out)) != SASL_OK)
msg_panic("%s: sasl_encode64 botch: %s",
myname, xsasl_cyrus_strerror(sasl_status));
return (XSASL_AUTH_MORE);
} else {
if (sasl_status == SASL_NOUSER) /* privacy */
sasl_status = SASL_BADAUTH;
vstring_strcpy(reply, xsasl_cyrus_strerror(sasl_status));
switch (sasl_status) {
case SASL_FAIL:
case SASL_NOMEM:
case SASL_TRYAGAIN:
case SASL_UNAVAIL:
return XSASL_AUTH_TEMP;
default:
return (XSASL_AUTH_FAIL);
}
}
}
/* xsasl_cyrus_server_first - per-session authentication */
int xsasl_cyrus_server_first(XSASL_SERVER *xp, const char *sasl_method,
const char *init_response, VSTRING *reply)
{
const char *myname = "xsasl_cyrus_server_first";
XSASL_CYRUS_SERVER *server = (XSASL_CYRUS_SERVER *) xp;
char *dec_buffer;
unsigned dec_length;
unsigned reply_len;
unsigned serveroutlen;
int sasl_status;
SERVEROUT_TYPE serverout = 0;
int xsasl_status;
#if SASL_VERSION_MAJOR < 2
const char *errstr = 0;
#endif
#define IFELSE(e1,e2,e3) ((e1) ? (e2) : (e3))
if (msg_verbose)
msg_info("%s: sasl_method %s%s%s", myname, sasl_method,
IFELSE(init_response, ", init_response ", ""),
IFELSE(init_response, init_response, ""));
/*
* SASL authentication protocol start-up. Process any initial client
* response that was sent along in the AUTH command.
*/
if (init_response) {
reply_len = strlen(init_response);
VSTRING_RESET(server->decoded); /* Fix 200512 */
VSTRING_SPACE(server->decoded, reply_len);
if ((sasl_status = SASL_DECODE64(init_response, reply_len,
dec_buffer = STR(server->decoded),
vstring_avail(server->decoded),
&dec_length)) != SASL_OK) {
vstring_strcpy(reply, xsasl_cyrus_strerror(sasl_status));
return (XSASL_AUTH_FORM);
}
if (msg_verbose)
msg_info("%s: decoded initial response %s", myname, dec_buffer);
} else {
dec_buffer = 0;
dec_length = 0;
}
sasl_status = SASL_SERVER_START(server->sasl_conn, sasl_method, dec_buffer,
dec_length, &serverout,
&serveroutlen, &errstr);
xsasl_status = xsasl_cyrus_server_auth_response(sasl_status, serverout,
serveroutlen, reply);
#if SASL_VERSION_MAJOR < 2
/* SASL version 1 doesn't free memory that it allocates. */
free(serverout);
#endif
return (xsasl_status);
}
/* xsasl_cyrus_server_next - continue authentication */
static int xsasl_cyrus_server_next(XSASL_SERVER *xp, const char *request,
VSTRING *reply)
{
const char *myname = "xsasl_cyrus_server_next";
XSASL_CYRUS_SERVER *server = (XSASL_CYRUS_SERVER *) xp;
unsigned dec_length;
unsigned request_len;
unsigned serveroutlen;
int sasl_status;
SERVEROUT_TYPE serverout = 0;
int xsasl_status;
#if SASL_VERSION_MAJOR < 2
const char *errstr = 0;
#endif
request_len = strlen(request);
VSTRING_RESET(server->decoded); /* Fix 200512 */
VSTRING_SPACE(server->decoded, request_len);
if ((sasl_status = SASL_DECODE64(request, request_len,
STR(server->decoded),
vstring_avail(server->decoded),
&dec_length)) != SASL_OK) {
vstring_strcpy(reply, xsasl_cyrus_strerror(sasl_status));
return (XSASL_AUTH_FORM);
}
if (msg_verbose)
msg_info("%s: decoded response: %.*s",
myname, (int) dec_length, STR(server->decoded));
sasl_status = SASL_SERVER_STEP(server->sasl_conn, STR(server->decoded),
dec_length, &serverout,
&serveroutlen, &errstr);
xsasl_status = xsasl_cyrus_server_auth_response(sasl_status, serverout,
serveroutlen, reply);
#if SASL_VERSION_MAJOR < 2
/* SASL version 1 doesn't free memory that it allocates. */
free(serverout);
#endif
return (xsasl_status);
}
/* xsasl_cyrus_server_get_username - get authenticated username */
static const char *xsasl_cyrus_server_get_username(XSASL_SERVER *xp)
{
const char *myname = "xsasl_cyrus_server_get_username";
XSASL_CYRUS_SERVER *server = (XSASL_CYRUS_SERVER *) xp;
VOID_SERVEROUT_TYPE serverout = 0;
int sasl_status;
/*
* XXX Do not free(serverout).
*/
sasl_status = sasl_getprop(server->sasl_conn, SASL_USERNAME, &serverout);
if (sasl_status != SASL_OK || serverout == 0) {
msg_warn("%s: sasl_getprop SASL_USERNAME botch: %s",
myname, xsasl_cyrus_strerror(sasl_status));
return (0);
}
if (server->username)
myfree(server->username);
server->username = mystrdup(serverout);
printable(server->username, '?');
return (server->username);
}
#endif